Env cascade light
env_cascade_lighting is a point entity available in Counter-Strike: Global Offensive. [[note: It is recommended to have a light_environment in your map to create radiosity based lighting, as this ent does not bake radiosity and only creates a real-time shadow map]]
It casts an extremely accurate shadow map via the "tools/slybox" texture, acting as a real-time variation of light_environment. This form of lighting is known as cascade shadow maps which works by rendering shadow maps at scaling resolutions based on the players initial camera vector from the center of a spatial grid. These shadow maps are then stitched together, with the the accuracy and quality of the shadow maps scaling lower the further they are away from the player, thus trading accuracy for performance.
HDR must be enabled to activate cascade lighting.